OBJECTIVE: To investigate trends in the incidence of epithelial ovarian cancer (EOC), according to histologic subtypes, in Korean women between 1999 and 2012. METHODS: Data from the Korea Central Cancer Registry recorded between 1999 and 2012 were evaluated. The incidences of EOC histologic subtypes were counted. Age-standardized incidence rates (ASRs) and annual percentage changes (APCs) in incidence rates were calculated. Patient data were divided into three groups based on age (<40, 40 to 59, and >59 years), and age-specific incidence rates were compared. RESULTS: Overall, the incidence of EOC has increased. Annual EOC cases increased from 922 in 1999 to 1,775 in 2012. In 1999, the ASR was 3.52 per 100,000 and increased to 4.79 per 100,000 in 2012 (APC, 2.53%; p<0.001). The ASRs in 2012 and APCs between 1999 and 2012 for the four major histologic subtypes were as follows (in order of incidence): serous carcinoma (ASR, 2.32 per 100,000; APC, 4.34%; p<0.001), mucinous carcinoma (ASR, 0.73 per 100,000; APC, -1.05%; p=0.131), endometrioid carcinoma (ASR, 0.51 per 100,000; APC, 1.48%; p=0.032), and clear cell carcinoma (ASR, 0.50 per 100,000; APC, 8.13%; p<0.001). In the sub-analyses based on age, clear cell carcinoma was confirmed as the histologic subtype whose incidence had increased the most since 1999. CONCLUSION: The incidence of EOC is increasing in Korea. Among the histologic subtypes, the incidence of clear cell carcinoma has increased markedly across all age groups since 1999.